This invention relates to catheters, and in particular to dilatation balloon catheters, for use in performance of percutaneous transluminal procedures including angioplasty.
Dilatation balloons currently used in percutaneous transluminal procedures have balloon working areas that are cylindrical in shape and whose diameter is substantially uniform throughout its working length. Such balloons typically have a working length of 20 mm. In certain circumstances, however, such dilatation balloons exhibit unacceptable performance characteristics. In particular, as shown in FIG. 4, when a standard dilatation balloon 42 is inserted and inflated in curved vascular segments, they tend to straighten the vascular walls 44. Additionally, as shown in FIG. 5, when a conventional dilatation balloon 52 is inflated in a lesion 54, the balloon can overdialate the vascular segments 56 adjacent to the lesion, particularly at high inflation pressures.
As a result, the use of "short" dilatation balloons has been attempted. Clinical experience with shorter balloon working lengths, e.g., 12 mm length PVC balloons, was expected to facilitate dilating lesions on vascular bends and discrete lesions. However, these short dilatation balloons tended to "squirt" out of the lesion upon inflation easier than standard length dilatation balloons.
Accordingly, there is a need in the art for dilatation balloons suitable for dilatation of lesions in curved arterial segments and discrete lesions.